[Hulka]

To me:

It’s either technology we have and don’t want the info leaked/uncovered

Or

It’s technology we don’t have and have no idea how it works

Or

It’s technology we don’t have and have no idea who has it

Or

This technology reveals a gap in our defenses we’d rather not admit our vulnerabilities.

Or

A combination of the above

[cgbg]

A very well researched and calm discussion of this topic:

https://www.amazon.com/UFOs-National-Security-State-Chronology/dp/1571743170

https://www.amazon.com/UFOs-National-Security-State-1973-1991/dp/0967799511/